A stamp-sized tear sensor could help detect Parkinson’s disease before major symptoms appear, researchers say.
The device is designed to detect dopamine, a brain chemical involved in movement, motivation and mood, using only a person’s tears.
The findings suggest tears could offer a needle-free way to help identify Parkinson’s disease and other conditions linked to dopamine.
A research team at the Federal University of Pelotas in Brazil developed the device and tested it in artificial human tears spiked with dopamine.
The sensor accurately detected concentrations ranging from well below a healthy baseline to three times above it, a range that includes levels previously reported in the tears of people with Parkinson’s disease.
Researchers said the device also performed reliably when other compounds were present.
To build the sensor, the team used a laser to burn patterns into a thin plastic film, turning parts of it into electrically conductive graphene.
Graphene is a thin form of carbon that conducts electricity. When dopamine molecules react with its surface, the device produces a measurable electrical signal.
“Our sensor can detect dopamine from levels well below the healthy baseline and up to three times higher,” Lucas Minghini Gonçalves, a co-author of the study, said in a statement.
He added that catching an early dopamine drop is “crucial to enabling timely, proactive therapeutic interventions.”
Current ways of tracking dopamine, including blood draws, urine tests and implanted devices, are often slow or invasive.
Tears, by contrast, can be collected in seconds without a needle.
The sensor has so far only been tested in artificial tears, not real tear samples.
Neftalí Lênin Villarreal Carreño, corresponding author and professor at the Federal University of Pelotas, said further testing would be needed before the device could become a diagnostic tool.
“Prior to validating our findings on real tears from Parkinson’s disease patients, we must submit our research protocol to a medical ethics committee for regulatory review,” Carreño said.
“Once that clears, our roadmap involves executing a baseline study with healthy control subjects to validate the sensor’s performance in standard physiological tear matrices.”
He said the team would then move on to “clinical validation using tear samples collected from patients diagnosed with Parkinson’s disease.”
If the sensor clears regulatory and technical hurdles, researchers say it could be relatively low cost.
“Currently, the estimated fabrication cost of the device at the laboratory scale averages approximately US$1 (RM4.09), and we anticipate that industrial-scale production will reduce this unit cost even further,” Carreño said.
Carreño said the team had not yet received proposals for commercialisation or licensing, but was setting up a spin-off company to help bring its healthcare sensors to market.
“We are currently in the process of establishing a startup spin-off to bring our healthcare sensors to market,” he added.
The researchers are also developing adapted sensors to identify other biomarkers, such as cortisol, a hormone linked to stress.
“Our team at the Novonano Research Group is already developing adapted sensors designed to identify alternative biomarkers, such as cortisol, a hormone directly linked to stress, enabling the comprehensive monitoring of multiple hormones rather than just dopamine within bodily fluids,” Carreño said.
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